package org.assistant.common.utils;

import java.security.MessageDigest;

public class StringUtils {
	// 16进制数组
	private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

	/**
	 * 转换字节数组为16进制字串
	 * 
	 * @param b
	 *            -字节数组
	 * @return 16-进制字串
	 */
	public static String byteArrayToHexString(byte[] b) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++) {
			resultSb.append(byteToHexString(b[i]));
		}
		return resultSb.toString();
	}

	/**
	 * 将字节转换为16进制字符串
	 * 
	 * @param b
	 * @return
	 */
	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n = 256 + n;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	/**
	 * 创建MD5码
	 * 
	 * @param source
	 * @return
	 */
	public static String MD5Encode(String source) {
		String resultString = source;
		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			resultString = byteArrayToHexString(md.digest(source.getBytes()));
		} catch (Exception ex) {
			resultString = source;
		}
		return resultString;
	}

	/**
	 * 加密密码
	 * 
	 * @param password
	 * @return
	 */
	public static String encodePassword(String password) {
		String encryptPwd = StringUtils.MD5Encode(password);
		int index = encryptPwd.length() / 4;
		String p = encryptPwd.substring(0, index);
		String s = encryptPwd.substring(index);
		encryptPwd = StringUtils.MD5Encode(p) + StringUtils.MD5Encode(s);
		return encryptPwd;
	}

	public static void main(String[] args) {
		String encryptPwd = StringUtils.MD5Encode("123456");
		int index = encryptPwd.length() / 4;
		String p = encryptPwd.substring(0, index);
		String s = encryptPwd.substring(index);
		encryptPwd = StringUtils.MD5Encode(p) + StringUtils.MD5Encode(s);
		System.out.println("encryptPwd = " + encryptPwd);
	}
}
